This invention relates to methods and apparatus for preventing undesired acceleration of a vehicle having an automatic engine speed control device.
German Offenlegungsschrift No. 30 21 489 discloses a conventional vehicle having a device for the synchronized shifting of a multiple speed transmission in which the shifting synchronization elements are not speed coordinated to the individual transmission operations. The synchronization of the transmission elements to be engaged is achieved by selective retarding or acceleration of the transmission drive shafts, under the influence of a control mechanism. In one embodiment of the invention disclosed in Offenlegungsschrift No. 30 21 489 the device that accelerates the transmission drive shaft is the vehicle engine For this purpose a device for increasing the engine speed which can be activated by the control mechanism is coordinated with the engine.
Arrangements of this type can cause a safety problem if erroneous operation of the device causes an increase in engine speed which is required for synchronization while the engine is coupled to the drive wheels of the vehicle, or if, because of erroneous operation of the coupling device between the engine and the drive wheels, the device for increasing engine speed is actuated while they are coupled. Such operation can result in acceleration of the vehicle that would startle the driver, and thus can considerably affect the safety operation of the vehicle.